Patent application title: Revolving Flat

Abstract:

A method for fastening a clothing strip (10) to a card-flat bar (21, 31)
by a fastening means in the form of clips (25, 35) is presented. In this
case, the clips (5, 25, 35) are integrally formed onto the card-flat foot
(23, 33) by press rams (12) guided simultaneously from both sides of the
card-flat bar (21, 31) and parallel to the plane of the clothing strip
(10). The clip (25, 35) integrally formed onto the card-flat foot (23,
33) loops around the latter with a looping angle (α) of less than
90° and more than 30° (degrees of angle). A corresponding
tool for carrying out the method and also a revolving card flat are
likewise proposed.

Claims:

1. Revolving card flat with a card-flat bar (21,31) which has a card-flat
foot (23, 33) and a web (22, 32) lying above the card-flat foot (23, 33),
and with a flexible clothing in the form of a clothing strip (10) and
with at least one fastening element in the form of a clip (25, 35), the
clip (25, 35) being attached with a first portion to the clothing strip
(10), being led with a second portion along one longitudinal side of the
card-flat bar (21, 31) and partially looping with a third portion around
the card-flat foot (23, 33) with a looping angle (α), characterized
in that the looping angle (α) amounts to less than 90.degree. and
to more than 30.degree..

2-12. (canceled)

Description:

[0001]The invention relates to a revolving card flat with a card-flat bar
which has a card-flat foot and a web lying above the card-flat foot, and
with a flexible clothing in the form of a clothing strip and with at
least one fastening element in the form of a clip, the clip being
attached with a first portion to the clothing strip, being led with a
second portion along one longitudinal side of the card-flat bar and
partially looping with a third portion around the card-flat foot with a
looping angle. The looping angle is defined as the angle between the
perpendicular, touching the side face of the card-flat foot, to the
clothing bearing face of the card-flat foot and that face of the
card-flat foot onto which the third portion of the clip is integrally
formed.

[0002]Various types of construction of revolving card flats are known from
the prior art. Revolving card flats are used in carding. The revolving
card flats employed nowadays consist essentially of a card-flat bar with
a clothing. The card-flat bar is composed of a card-flat foot and of a
web lying above the latter. The clothing is fastened to the card-flat
foot with the aid of clips. The clothing itself is used in the form of
clothing strips, on the underside of which a multiplicity of clothing
needles in the form of small wire hooks are fastened. At the two ends of
a card-flat bar, devices are provided which make it possible to fasten
the card-flat bar to a chain or a belt.

[0003]U.S. Pat. No. 581,749 discloses a revolving card flat and a
corresponding tool for fastening the clothing strip to the card-flat
foot. In this case, first, the clips are connected to the clothing strip.
In a further step, the clothing strip thus prepared is joined together
with the card-flat bar, and subsequently the free portions of the clips
are bent around the card-flat foot, so that the clothing strip comes to
lie, free of play, on the card-flat foot. The card-flat foot is in this
case surrounded by the clips in a bracket-like manner. To make this
connection between the card-flat foot and clothing strip by means of
clips, a complicated movement of the too used is necessary.

[0004]DE 128 552 likewise discloses the fastening of a flexible clothing
in the form of a clothing strip to the card-flat foot of a card-flat bar.
The clip used in this case, on the one hand, engages into the foundation
of the clothing strip and, on the other hand, engages around or surrounds
the card-flat foot. This makes it possible for the lining material of the
foundation of the clothing strip to lie firmly on the card-flat foot.
Here, too, the disadvantage is that clips bent on both sides have to be
manufactured.

[0005]FIG. 1 shows a device, such as is used for drawing clothing strips
onto card-flat bars. The card-flat bar 1 is built onto a clothing strip
10 previously laid into a holding device 8, so that the card-flat foot 3
comes to lie on the clothing strip. The clips 5 are already fastened to
the clothing strip 10 on longitudinal sides of the latter. The card-flat
bar 1 is consequently introduced with the card-flat foot 3 between the
clips 5. With the aid of prebending rollers 6, the clips 5 are preformed.
In a second step, by means of the form rollers 7, the clips 5 are
integrally formed onto the card-flat foot 3. The prebending rollers 6 and
form rollers 7 are moved in the longitudinal direction of the card-flat
bar 1 for the integral formation of the clips 5, while the rollers rotate
and are pressed against the card-flat foot 3. The device shown has the
disadvantage that only a specific shape of the card-flat foot 3 fits
together with the predetermined form rollers 7. Also, complicated
movement and clamping mechanisms are necessary so that the operation
described above can be carried out.

[0006]WO 2006/039829 discloses a further example of a device for attaching
a clothing strip to a card-flat bar. A prepared clothing strip, in which
the clips are already fastened with a first portion on both sides, is
introduced into the device. The card-flat bar is subsequently introduced,
with the card-flat foot against the clothing strip, into the device, so
that the clips lead with a second portion along the longitudinal sides of
the card-flat foot. The bending cheeks of the device are then pivoted
inwards against the card-flat bar, with the result that the third portion
of the clips is integrally formed onto the card-flat foot. To generate
the necessary holding force, in addition, a deformation of the clips
along the longitudinal sides of the card-flat foot is generated by means
of press battens. One disadvantage of the device is that a plurality of
movements of pressing tools and bending cheeks are necessary in order to
achieve a fastening of the clothing to the card-flat bar. Also, there is
the risk that, in the case of excessive deformation of the clip, a change
in shape of the overall card-flat bar may occur, because various elements
of the card-flat foot are spanned by the clips.

[0007]The prior art for fastening clothing strips to card-flat bars with
the aid of clips likewise entails the disadvantage that the card-flat
foot has to be subjected over its entire length and width and also its
height to a narrow manufacturing and dimensional tolerances. In order to
achieve a reliable fastening of the clothing strips, an exact
co-ordination of the pressing tool, form rollers and dimensions and shape
of the card-flat foot with the dimensions of the clips and their material
properties is necessary. This leads to a cost-intensive production of the
individual parts and also of the equipment necessary for assembling them.

[0008]The object of the present invention, then, is to avoid the
disadvantages of the prior art and to provide a simple connection between
the card-flat foot and clothing, without having to allow for any loss of
holding force.

[0009]The object is achieved by means of the type of construction of a
revolving card flat of the type mentioned in the introduction and by
means of the method and the tool necessary for this, having the
characterizing features of the independent claims 1, 6 and 10. The object
is achieved in that the clip loops with a third portion around the
card-flat foot with an angle of between 90° and 30°
(degrees of angle).

[0010]A revolving card flat according to the invention has a card-flat
bar. The card-flat bar is composed of the card-flat foot and of a web
lying above the card-flat foot. Card-flat bars are nowadays produced
mostly in one piece from steel or cast iron and also in the form of
hollow profiles consisting of light metal or light metal alloys.
Card-flat bars consisting of plastic or of composite materials may also
be envisaged. A clothing is attached to that side of the card-flat foot
which lies opposite the web, the clothing bearing face of the card-flat
bar. In this case, mostly, flexible clothings are used. A flexible
clothing comprises a foundation which is constructed from a plurality of
fabric layers and which is pierced by needles. The clothing is produced
in the form of strips, the width and length of these clothing strips
corresponding to the dimensions of the card-flat foot. The clothing
strips and the card-flat foot are held together along the longitudinal
sides of the card-flat foot with the aid of fastening elements, what are
known as clips. The clips have a first portion which is connected to the
clothing strip. This takes place mostly by pricking into the foundation
and by subsequently bending round the clips, so that a second portion of
the clips leads along the lateral longitudinal edges of the clothing
strip, parallel to the side faces of the latter or the longitudinal edges
of the card-flat foot, in the direction of the web. A third portion of
the clips then projects away from the clothing strip beyond the card-flat
foot.

[0011]There has previously been the conviction that a sufficiently high
holding force for operational requirements between the card-flat foot and
the clothing strip can be achieved only by a crimping of the clip. This
meant bending the third portion of the clip around through more than
90°, thus resulting in a looping around of the card-flat foot of
more than 90°. Bending around resulted in a bracketing of the
card-flat foot, which was intended to prevent the clip from slipping off
laterally. According to the invention, however, by the clip being
integrally formed onto the contour of the card-flat foot, a holding force
sufficient for the requirements can be achieved even in a case of a
looping around of less than 90°. Fastening the clothing strip
simultaneously from both sides gives rise in the clothing strip to a
tension which assists the frictional connection achieved by the clip
fitting snugly against the card-flat foot. The frictional connection is
achieved by the card-flat foot being looped around by the third portion
of the clip. In this case, it was shown that a looping around of less
than 90° leads, between the card-flat foot and the clip, to a
frictional connection which fulfils the requirements to be met during
operation by the connection of the card-flat foot and clothing strip. As
regards the production and releasability of the connection, a looping
angle of less than 70°, in particular of 60°, proved to be
advantageous. In order to obtain a sufficiently high holding force via
the frictional connection, a looping angle of more than 30°,
preferably of more than 50°, is advantageous.

[0012]In a preferred version of the invention, the clip is manufactured
from light metal or a light metal alloy. The necessary forces for
integrally forming the clip onto the card-flat bar are thereby reduced.
In particular, the use of clips consisting of aluminium or of an
aluminium alloy has proved appropriate. The card-flat bars, too, may be
produced from light metal or a light metal alloy. In particular, the
card-flat bars may be designed as hollow profiles. The use of aluminium
or of an aluminium alloy is also advantageous.

[0013]The method for integrally forming the clips onto the card-flat foot
is characterized by the use of simple press rams. The press rams in this
case act simultaneously from both sides of the card-flat bar on the clips
to be integrally formed. The press rams are in this case to be moved
towards one another transversely to the longitudinal direction of the
card-flat bar. The movement of the press rams takes place linearly in a
plane which is parallel to the plane of the clothing strip. The press
rams may be provided with a drive. The drive may take place electrically,
pneumatically or hydraulically. A purely mechanical drive which can be
actuated by hand may also be envisaged.

[0014]In a preferred version, the card-flat bar has above the card-flat
foot an additional rib which leads along, parallel to the card-flat foot,
over the length of the card-flat bar. The rib in this case forms,
together with the card-flat foot, a guide for the press rams. The press
rams are guided by this rib in their movement in such a way that they
cannot avoid the clip.

[0015]The press rams are preferably manufactured from an elastic material,
preferably from a thermoplastic, in particular polyethylene or polyamide.
As a result, that part of the press ram which slides along on the
card-flat foot and the third portion of the clip is deformed. Owing to
this deformation, the press ram adapts to the contour of the clip and of
the card-flat foot, thus leading to the clip being integrally formed onto
the card-flat foot. By the clip being integrally formed exactly onto the
contour of the card-flat foot in this way, unevenesses in the card-flat
foot can be compensated. A compensation of production or dimensional
tolerances on the card-flat bar is also possible. Already used and
therefore slightly damaged card-flat bars may be reequipped with a
clothing strip by means of the proposed method. When the pressing
operation has ended, the rams are retracted and resume their original
shape.

[0016]The tool used for carrying out the method makes it possible to
receive a card-flat bar. The clothing strip, together with the clips
already fastened to it, and the card-flat bar are introduced into the
tool. The clothing strip and the card-flat bar are subsequently retained
in their position with respect to one another. For this purpose, means
are provided which, on the one hand, make it possible to position the
clothing strip and card-flat bar, for example guides, and, on the other
hand, fix this position, for example cramp it or clamp it.
Advantageously, the card-flat bar is attained during the following
pressing operation by means of a holding-down device. The press rams
moving forwards simultaneously from both sides may be manufactured in one
piece and extend over the entire length of the clothing strip to be
fastened. A division of the press ram into individual segments may also
be envisaged, in which case the drive for the press ram may likewise be
apportioned to individual segments.

[0017]The invention is explained in more detail below with reference to
exemplary embodiments and by means of drawings in which:

[0018]FIG. 1: shows a diagrammatic illustration of a device for assembly
of a card-flat bar and clothing according to the prior art;

[0019]FIG. 2: shows a diagrammatic illustration of a cross section of a
first revolving card flat according to the invention;

[0020]FIG. 3: shows a diagrammatic illustration of a cross section of a
second revolving card flat according to the invention;

[0021]FIG. 4: shows a view of a detail of the fastening of a clothing
strip to the card-flat foot;

[0022]FIG. 5: shows a diagrammatic illustration of the tool for producing
a revolving card flat according to the invention;

[0023]FIG. 6: shows a diagrammatic illustration of a cross section of a
revolving card flat according to the invention during a pressing
operation.

[0024]FIG. 1 shows an arrangement, conventional according to the
present-day prior art, of a device for assembly of a card-flat bar and
clothing strip to form a revolving card flat. The figure was discussed in
detail under the prior art, and therefore a further description is
dispensed with at this juncture.

[0025]FIG. 2 shows a cross section of a revolving card flat according to
the invention. The clothing strip 10 consists of the foundation 9 and of
the needles 4 which are held in the latter and which constitute the
actual clothing. The clothing strip is held on the card-flat foot 23 on
each of the two sides by means of a clip 25. The card-flat foot 23 and
the web 22 located above it form the card-flat bar 21. This card-flat bar
21 is provided (not illustrated) at its outer ends with a card-flat end
head in each case.

[0026]FIG. 3 shows a cross section of a further revolving card flat
according to the invention. The card-flat bar 31 is designed as a hollow
profile, the hollow profile increasing in width towards the clothing
strip 10 and forming the web 32. A card-flat foot 33 is formed at the
lower end of the hollow profile. The slender part of the hollow profile
in this case forms the web 32. A rib 11 is integrally formed on the web
32 on both sides above the card-flat foot 33 and runs over the entire
length of the card-flat bar 31. A clothing strip 10 is attached on that
side of the card-flat foot 33 which lies opposite the web 32, the
clothing bearing face. The clothing strip 10 is held on the card-flat
foot 33 by means of clips 35 attached to the longitudinal sides of the
card-flat bar 31.

[0027]FIG. 4 shows a view of a detail from FIG. 3. The clothing strip 10
consisting of the foundation 9 and of the clothing 4 is fastened to the
card-flat foot 33 by means of the clip 35. The web 32 is laid, opposite
the clothing strip 10, against the card-flat foot 33. The card-flat bar
31 is produced in one piece, so that the card-flat foot 33 and the web 32
merge one into the other without any visible parting line. The clip 35 is
illustrated, laid out, in a side view in the further part of FIG. 4. In
this case, the region A constitutes a first portion of the clip 35. This
is provided at the outer margin with serrations which, in the fastened
state, engage into the foundation 9 of the clothing strip 10. The region
B designates a second portion of the clip 35 which, in the installed
state, is led along the longitudinal side of the clothing strip or of the
card-flat foot. The region C constitutes a third portion of the clip 35.
This is integrally formed onto the card-flat foot 33 and loops around the
latter at the angle α. The looping angle α is defined as the
angle between the perpendicular, touching the side face of the card-flat
foot 33, to the clothing bearing face of the card-flat foot 33 and that
face of the card-flat foot 33 onto which the third portion (region C) of
the clip 35 is integrally formed. The third portion (region C) of the
clip 35 is bent away at the looping angle α out of alignment with
the second portion (region B) of the clip 35, so that this third portion
(region C) bears against the card-flat foot 33.

[0028]FIG. 5 shows diagrammatically the tool for fastening the clothing
strip 10 to the card-flat bar 21, 31. The half, designated by L, of FIG.
5 illustrates a card-flat bar 21 according to FIG. 2. The half,
designated by R, of FIG. 5 illustrates a card-flat bar 31 according to
FIG. 3. Irrespective of the differences between the two card-flat bars
21, 31, the procedure is the same for fastening the clothing strips 10 to
the card-flat bars 21, 31 or card-flat feet 23, 33. The clothing strip 10
is introduced into a receptacle 14 in the tool. In this case, a
depression is arranged centrally in the receptacle 14 over the length of
the card-flat bar 21, 31, so that the clothing strip 10 is not damaged
during the fastening operation. The clips 25, 35 have in this case
already been attached to the clothing strips 10 beforehand. The regions B
and C of the clips 25, 35 are located in a plane which runs (not
illustrated) advantageously perpendicularly to the foundation 9. The
card-flat bar 21, 31 is introduced from above between the regions B and C
of the clips 25, 35 (see FIG. 4). By means of a holding-down device 13,
the card-flat bar 21, 31, together with the clothing strip 10 lying
beneath it, is pressed against the receptacle 14 and thus fixed. The
card-flat bar 21, 31 and clothing strip 10 are thus tension-mounted
between the receptacle 14 and the holding-down device 13 engaging on the
web 23, 33.

[0029]In a next step, the two press rams 12 are led simultaneously up to
the card-flat bar 21, 31 from both sides of the latter. The press ram 12
presses the third portion (region C) of the clip 25, 35 against the
card-flat foot 23, 33 upon further movement. As a result, the third
portion of the clip 25, 35 is integrally formed onto the card-flat foot
23, 33 by the press ram 12. The press ram 12 is preferably manufactured
from an elastic material, so that it slides over the third portion of the
clip 25, 35, while the press ram 12 adapts to the contour of the
card-flat foot 23, 33. As a result of this type of "bending" of the third
portion of the clip 25, 35, the second portion of the clip 25, 35 is
drawn upwards against the ram 12. Since this effect occurs on both sides
of the card-flat foot 23, 33, the clothing strip 10 is drawn apart and
tensioned.

[0030]In the half, designated by R, of FIG. 5, in a preferred version of
the invention, the rib 11 is formed above the card-flat foot 33. The rib
11 is shaped in such a way that its inclination gives rise to a
preferably symmetrical depression between the rib 11 and the card-flat
foot 33, together with the inclination of the surface of the card-flat
foot 33. The middle of the press ram 12 preferably runs congruently with
the middle of this depression. The connecting line between the middle of
the depression and the middle of the press ram 12 corresponds at the same
time to the direction of linear movement of the press ram 12.

[0031]In the half, designated by L, of FIG. 5, there is no rib 11 present
in the version of the card-flat bar 21, as shown. As a replacement for
the absent rib 11, but with the same function, to be precise that of
avoiding an evasion of the press ram 12, a ram guide 15 is attached to
the ram 12 itself. The ram guide 15 is advanced together with the press
ram 12. As a result, the insertion of the clothing strip 10 and of the
card-flat bar 21 is not impeded when the press rams 12 are in their
initial position, as illustrated in FIG. 5. Owing to this measure, the
application of the method does not depend on a type of construction of
the card-flat bar which is specifically co-ordinated with it.

[0032]The press rams 12 may be moved by means of mutually independent
linear drives. The drive may be of the electrical, pneumatic or hydraulic
type of construction. A connection of the press rams 12 may also be
envisaged, for example by means of a linkage, in order to move both press
rams 12 by means of the same drive. A mechanical drive actuated by hand
may likewise be provided. If the holding-down device 13, too, is provided
with a drive, an automatic flow of the overall method may be envisaged.

[0033]FIG. 6 shows a detail of the cross section of a revolving card flat
according to the invention from the right half, designated by R, of FIG.
5 during the pressing operation, the press ram 12 being shown in the
foremost position. The press ram 12 is pressed against the card-flat foot
33 with the force F. On account of its elasticity, the front part 16 of
the press ram 12 which has penetrated into the depression between the
card-flat foot 33 and the rib 11 is deformed. The deformed part 16 of the
press ram 12 fills the entire depression, adapts to the contour and is
partially upset. With the press ram 12 being adapted with its front part
16 to the contour of the depression by pressing with the force F, the
card-flat bars 31 can be manufactured with greater tolerance in terms of
the shape of that side of the card-flat foot 33 which lies opposite the
clothing strip 10 and of the rib 11. Also, after being used more than
once, the card-flat bars 31 can be reused without any remachining of the
faces and shapes against which the clip 35 bears.

[0034]The force F to be applied is to be co-ordinated with the selected
elasticity of the press ram 12, with the contour of the card-flat bar 31
to be filled and with the clip 35 selected for fastening the clothing
strip 10.